Computer systems come in a variety of topologies. Systems that include multiple data processing modules (or nodes) often have complex topologies. The interconnection assemblies that connect the modules of such topologies are often complicated, as well. In particular, it is a demanding task for an interconnection assembly to provide several connections (or links) to each module, as required by certain systems having mesh-shaped and torus-shaped configurations.
A typical multi-module computer system has an interconnection assembly that includes a backplane, module connectors and flexible wire cables. The backplane is a rigid circuit board to which the module connectors are mounted. Each module is a circuit board that electrically connects with the backplane when plugged into one of the mounted module connectors. The flexible wire cables connect with the backplane to configure the system into a network topology having a particular size.
The network topology of a typical multi-module computer system is expandable by adding another backplane and reconnecting the flexible wire cables to configure the system into a larger network topology. Generally, the topology of the system is expanded by several modules at a time. For example, one such system having a 4×4×4 torus topology is expanded by adding a 16-module backplane and reconnecting the flexible wire cables to expand the system to a 4×4×5 torus topology. As another example, in a system having 2-D mesh topology, the minimum unit of expansion is a backplane that adds four modules to the system. Some systems permit expansion by hot-plugging, i.e., plugging and unplugging cables to expand the topology of the system while the power remains on.
Examples of some conventional systems that are expandable by several modules at a time are the Paragon made by Intel Corp., of Santa Clara, Calif., and the Cray T3D/T3E made by Cray Research Corp., of Eagan, Minn.